Predominant phosphatase in the ocular lens regulated by physiological concentrations of magnesium and calcium.

A magnesium-dependent phosphatase with a molecular weight of about 55 kDa was found in the lens of chicken embryo, mouse, rabbit and bovine. It appears to be unique to the lens and, when activated by magnesium, accounts for the majority of the phosphatase activity in the lens. Phosphatases in the lens were separated by using high-resolution gel permeation column chromatography, and phosphatase activity was determined with p-nitrophenyl phosphate (pNPP) as a substrate.